{x+y-2z=-3 2x+6y+z=2 x+y+z=0

题目

{x+y-2z=-3 2x+6y+z=2 x+y+z=0

答案

x+y-2z=-3 ①
2x+6y+z=2 ②
x+y+z=0 ③
③-①得3z=3 z=1
将z=1代入①和②
得x+y=-1 ④
2x+6y=1 ⑤
④×2-⑤
得-4y=-3
y=3/4
将y=3/4代入④
得x=-7/4